A wide variety of arrangements have been utilized for conditioning air by increasing the air humidity. The benefits of maintaining proper humidity levels in a home are well documented. As the house heats up it can easily become dry. Hardwood floors and stairs creak from a lack of moisture. Other wood furnishing can literally dehydrate and shrink, developing cracks in their finish and gaps between their joints.
A proper humidity level also makes a house more comfortable for people living in it. Dry air can even feel colder than actual thermostat settings. A humidifier system can help lower heating bills by adding humidity, which actually makes the air feel warmer.
There are many types of humidifiers, for example, drum humidifiers, flow-through humidifiers, and steam-powered humidifiers. Drum humidifiers include a pad mounted to a motorized cylindrical drum. A motor rotates the pad through a reservoir of water as air is bypassed through the pad to become humidified. The humidified air is mixed with return air. Humidifier drums however need frequent maintenance, requiring cleanout every month or two to prevent evaporative water buildup in the reservoir and on the pad.
Flow-through humidifiers use a portion of the air supplied by a furnace, which is sent through a bypass duct to generate airflow across a water saturated humidifier pad. The humidified air is then routed back to the return side of the furnace where it is blended with air from the cold air return, heated, and returned to the home environment. Flow through units deliver humidity to the home only when the furnace is operating. In cases where there is not enough furnace run-time, such as in a climate with a mild winter, proper levels of humidity are not maintained.
Steam powered humidifiers are an alternative that provides more consistent humidity because they deliver rated humidification on demand, independent of the furnace run time. A steam powered humidifier typically mounts under a supply or return air duct and has a heating element that boils water in a reservoir when a humidistat calls for additional humidity. If humidity is called for, the system will turn on the furnace fan to distribute the humidity. Similar to the drum humidifiers, however, conventional steam powered humidifiers require frequent cleanout maintenance to eliminate evaporative water buildup in the reservoir and on the heating element.
Whole house residential humidifiers that incorporate water reservoirs are susceptible to multiple modes of failure due to contaminants in the supply water. Systems that use direct immersion heating elements or rotating evaporative drums, act as collectors for solid content, since the water quality on the supply side is uncontrolled. The solid content can accumulate and lead to premature failure of, for example, the heating element in steam humidifiers, or loss of absorptive capacity of the evaporative elements.
Periodic flushing can mitigate the solid content accumulation problem. There are a number of reasons why flushing does not, however, fully address the accumulation of solids. For example, periodic flushing does not remove solids that are deposited to surfaces. Reservoir and drain configurations do not always allow solids to leave the device even when water is flushed through the device. In addition, the quality of water supply varies greatly between municipalities, which makes the application and maintenance of conventional systems difficult unless specific water conditions at the installing location are known.
One of the bigger product issues for steam humidifiers is the failure of the internal heating element. This failure is predominantly attributed to poor water quality causing a residue build-up on the heating element. Over time, this build-up causes the heating element to deteriorate and fail.
In general, improvement has been sought with respect to such humidifier systems, generally to reduce maintenance, improve efficiency, and improve system reliability.